1. Field of the Invention
This application relates to electromagnetic radiating structures suitable for use as antennas and in electromagnetic field test facilities used for observing the behaviour of equipment in the presence of strong electromagnetic fields and for detecting radiation from the equipment.
Continuous Wave (cw) measurement of electromagnetic susceptibility and radiated interference have been carried out using multiple antennas whose electromagnetic properties must be well known in the near field or using TEM cells whose volume and/or frequency limits make them unsuitable for broadband testing of large electronic sub-systems more than a few meters in height.
2. Background Information
Electromagnetic field test facilities described as "simulators" are disclosed in U.S. Pat. No. 5,440,316 issued Aug. 8, 1995 and U.S. Pat. No. 5,982,331 issued Nov. 8, 1995 both to Podgorski. The structure shown in FIGS. 1 and 2 of U.S. Pat. No. 5,982,331 is an electromagnetic field test facility employing vertically polarized electromagnetic waves in the test area and the structure shown in FIG. 3 of U.S. Pat. No. 5,982,331 is an electromagnetic field test facility employing horizontally polarized waves in the test area of a semi-anechoic chamber. The structure shown in FIGS. 9 and 10 of U.S. Pat. No. 5,982,331 is an electromagnetic field test facility employing vertically polarized electromagnetic waves in the test area and the structure shown in FIG. 12 of U.S. Pat. No. 5,982,331 is an electromagnetic field test facility employing horizontally polarized waves in the test area of an anechoic chamber.
Recently issued Bellcore's Generic Requirements Criteria GR 1089-CORE, for telecommunications equipment, indicates the need for apparatus to perform E-field (electric field) radiated immunity and emission testing from 10 kHz to 10 GHz, and H-field (magnetic field) radiated emission testing from 60 Hz to 30 MHz.
The current requirement for the standard size of testing facilities is a distance between the test antenna and the tested object of 3 m, 5 m, and 10 m with the size of testing area limited to 1.5 m.times.1.5 m. The broadband Gigahertz field electromagnetic field test facility of U.S. Pat. No. 5,982,331 can fulfil the standard facility size requirements with the frequency of operation from DC to 5 GHz. If the size of the testing area is limited to 0.5 m.times.0.5 m, the existing configuration of the broadband Gigahertz field facility allows it to exceed the upper frequency limit of 10 GHz dictated by Bellcore GR 1089-CORE.